Pediatric brainstem cavernous malformations: 2-center experience in 40 children

OBJECTIVE

Brainstem cavernous malformations (BSCMs) are relatively uncommon, low-flow vascular lesions in children. Given the paucity of data, guidelines regarding the clinical management of BSCMs in children are lacking and the surgical indication is most commonly based on an individual surgeon's judgment and experience. The goal in this study was to evaluate the clinical behavior of BSCMs in childhood and the long-term outcome in children managed conservatively and surgically.

METHODS

This was an observational, retrospective study including all children with BSCMs who were followed at 2 institutions between 2008 and 2020.

RESULTS

The study population consisted of 40 children (27 boys, 67.5%) with a mean age of 11.4 years. Twenty-three children (57.5%) were managed conservatively, whereas 17 children (42.5%) underwent resection of BSCMs. An aggressive clinical course was observed in 13 children (32.5%), who experienced multiple hemorrhages with a progressive pattern of neurological decline. Multiple BSCMs were observed in 8 patients, of whom 3 patients presented with a complex of multiple tightly attached BSCMs and posed a significant therapeutic challenge. The overall long-term outcome was favorable (modified Rankin Scale [mRS] scores 0-2) in 36 patients (90%), whereas an unfavorable outcome (mRS scores 3 and 4) was seen in 4 children (10%). An mRS score of 5 or 6 was not observed. The mean (± SD) follow-up was 88.0 (± 92.6) months.

CONCLUSIONS

The clinical course of BSCMs in children is highly variable, with benign lesions on the one hand and highly aggressive lesions with repetitive hemorrhages on the other. Given the greater life expectancy and the known higher functional recovery in children, surgical treatment should be considered early in young patients presenting with surgically accessible lesions and an aggressive clinical course, and it should be performed in a high-volume center.

Two different prenatal imaging cerebral patterns of tubulinopathy

To illustrate the prenatal cerebral imaging features associated with tubulinopathy, we report on five affected fetuses from unrelated families, with a de-novo heterozygous variant in a tubulin gene (TUBA1A, TUBB2B or TUBB3). We identified two distinct prenatal imaging patterns related to tubulinopathy: a severe form, characterized by enlarged germinal matrices, microlissencephaly and a kinked brainstem; and a mild form which has not been reported previously in the prenatal literature. The latter form is associated with non-specific features, including an asymmetric brainstem, corpus callosal dysgenesis, a lack of Sylvian fissure operculization and distortion of the anterior part of the interhemispheric fissure with subsequent impacted medial borders of the frontal lobes, the combination of which, in the absence of additional extracerebral anomalies, is highly suggestive of tubulinopathy. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

A novel de novo mutation in the PURA gene associated with a new clinical finding: large brainstem

We report the case of a Caucasian Spanish boy, who showed profound neonatal hypotonia, feeding difficulties, apnea, severe developmental delay, epilepsy, bilateral convergent strabismus, poor verbal language development and a large brainstem. Whole-exome sequence uncovered a novel de novo mutation in the purine-rich element binding protein A gene (PURA; NM_005859.4:c.72del:p.(-Gly25AlafsTer53)) that encodes the transcriptional activator protein Pur-alpha (PURA). Mutations in this gene have been identified in patients with PURA syndrome, a rare disorder characterized by an early hypotonia, developmental delay, severe intellectual disability with or without epilepsy, and disability in expressive language development. Although, up to 75 cases have been identified worldwide, to the best of our knowledge, this is the first patient described with a brainstem larger than normal. In conclusion, our data expand both geneticand phenotypic spectrum associated with PURA gene mutations.

Structural and Functional Aberrations of the Auditory Brainstem in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with difficulties in the social, communicative, and behavioral domains. Most cases of ASD arise from an unknown etiologic process, but there are numerous risk factors, including comorbidities and maternal exposures. Although it is not part of the diagnostic criteria, hearing difficulties ranging from deafness to hyperacusis are present in the majority of persons with ASD. High-functioning children with ASD have been found to have significantly slower and asymmetric auditory brainstem reflexes. Additionally, histopathological studies of postmortem brainstems in decedents who had ASD have consistently revealed significantly fewer neurons in auditory nuclei compared with those in people who did not have ASD. The authors review the literature implicating auditory dysfunction in ASD along with results from human study participants and postmortem human brain tissue. Together, these results implicate significant structural and functional abnormalities in the auditory brainstem in ASD and support the utility of auditory testing to screen for ASD.

Loss of Protocadherin-12 Leads to Diencephalic-Mesencephalic Junction Dysplasia Syndrome

OBJECTIVE

To identify causes of the autosomal-recessive malformation, diencephalic-mesencephalic junction dysplasia (DMJD) syndrome.

METHODS

Eight families with DMJD were studied by whole-exome or targeted sequencing, with detailed clinical and radiological characterization. Patient-derived induced pluripotent stem cells were derived into neural precursor and endothelial cells to study gene expression.

RESULTS

All patients showed biallelic mutations in the nonclustered protocadherin-12 (PCDH12) gene. The characteristic clinical presentation included progressive microcephaly, craniofacial dysmorphism, psychomotor disability, epilepsy, and axial hypotonia with variable appendicular spasticity. Brain imaging showed brainstem malformations and with frequent thinned corpus callosum with punctate brain calcifications, reflecting expression of PCDH12 in neural and endothelial cells. These cells showed lack of PCDH12 expression and impaired neurite outgrowth.

INTERPRETATION

DMJD patients have biallelic mutations in PCDH12 and lack of protein expression. These patients present with characteristic microcephaly and abnormalities of white matter tracts. Such pathogenic variants predict a poor outcome as a result of brainstem malformation and evidence of white matter tract defects, and should be added to the phenotypic spectrum associated with PCDH12-related conditions. Ann Neurol 2018;84:646-655.

Brainstem dysgenesis: beyond Moebius syndrome

Brainstem dysgenesis designates all those patients with congenital dysfunction of cranial nerves and muscle tone due to prenatal lesions or malformations of the brainstem. This generic term has the advantage over the eponyms Moebius 'expanded' or 'unrestricted', Robin, Cogan or Carey-Fineman-Ziter syndromes in that it has a less restrictive view and provides a frame work that enables a systematic approach to diagnosis and research of most developmental disorders involving the brainstem. The review of the literature and our experience shows that infants with a predominant rombencephalic involvement are due to brainstem prenatal disruptive vascular accidents, while cases with midbrain and cerebellar involvement and widespread malformative syndromes have most likely an underlying genetic cause. Due to phenotypic heterogeneity associated with brainstem dysgenesis, it is crucial to evaluate each case individually and to establish a specific therapeutic plan. Intervention programs should start soon after diagnosis and directed to improve functions needed for daily life activities. Even though the prognosis of patients with brainstem dysgenesis due to prenatal destructive lesions depends on the magnitude of the vascular territory involved, in most patients with brainstem dysgenesis, the prognosis is better than the initial clinical manifestations would indicate.

Cervico-Oculo-Acoustic Syndrome in a Male with Consanguineous Parents

Background:

The cervico-oculo-acoustic syndrome comprises Klippel-Feil anomaly, sensorineural deafness and Duane's retraction syndrome. Polygenic, autosomal dominant, and X-linked inheritance have been hypothesized. The disorder has rarely been reported in males.

Case Report:

A 42-year-old male, born of consanguineous parents, presented with Duane's syndrome, mixed hearing loss, C2-C3 fusion, neck stiffness, and right facial palsy. A variety of cardiac, neurological and urogenital anomalies occurred in his relatives. The electro-oculographic studies showed impaired abduction and adduction of the right eye and impaired abduction of the left eye. Vergence, vertical eye movements and peripheral vestibular responses were normal. Somatosensory evoked potentials showed absence of the N13 peak and brainstem auditory evoked potentials bilateral delay of the I-III interpeak latencies.

Conclusions:

Consanguinity of the patient's parents, not previously reported, suggests autosomal recessive inheritance, but autosomal dominant inheritance is indicated by the family history. The pattern of the oculomotor deficit is consistent with bilateral dysplasia of the abducens nuclei with preserved internuclear neurons in the right abducens nucleus. Neurophysiological investigations revealed lower brainstem and cervical cord involvement.

Mutation of Npr2 leads to blurred tonotopic organization of central auditory circuits in mice

Tonotopy is a fundamental organizational feature of the auditory system. Sounds are encoded by the spatial and temporal patterns of electrical activity in spiral ganglion neurons (SGNs) and are transmitted via tonotopically ordered processes from the cochlea through the eighth nerve to the cochlear nuclei. Upon reaching the brainstem, SGN axons bifurcate in a stereotyped pattern, innervating target neurons in the anteroventral cochlear nucleus (aVCN) with one branch and in the posteroventral and dorsal cochlear nuclei (pVCN and DCN) with the other. Each branch is tonotopically organized, thereby distributing acoustic information systematically along multiple parallel pathways for processing in the brainstem. In mice with a mutation in the receptor guanylyl cyclase Npr2, this spatial organization is disrupted. Peripheral SGN processes appear normal, but central SGN processes fail to bifurcate and are disorganized as they exit the auditory nerve. Within the cochlear nuclei, the tonotopic organization of the SGN terminal arbors is blurred and the aVCN is underinnervated with a reduced convergence of SGN inputs onto target neurons. The tonotopy of circuitry within the cochlear nuclei is also degraded, as revealed by changes in the topographic mapping of tuberculoventral cell projections from DCN to VCN. Nonetheless, Npr2 mutant SGN axons are able to transmit acoustic information with normal sensitivity and timing, as revealed by auditory brainstem responses and electrophysiological recordings from VCN neurons. Although most features of signal transmission are normal, intermittent failures were observed in responses to trains of shocks, likely due to a failure in action potential conduction at branch points in Npr2 mutant afferent fibers. Our results show that Npr2 is necessary for the precise spatial organization typical of central auditory circuits, but that signals are still transmitted with normal timing, and that mutant mice can hear even with these deficits.

[Brainstem dysgenesis: functional prognosis and rehabilitative treatment. A series of nine cases]

INTRODUCTION

Brainstem dysgenesis is a heterogeneous clinical entity, with low incidence and high clinical variability, which affects structures in the brainstem. Diagnosis is based on the combination of symptoms, neuroimaging and neurophysiological studies.

AIM

To determine the common clinical features, functional prognosis and rehabilitative treatment needs in a group of children with brainstem dysgenesis.

PATIENTS AND METHODS

Observation-based retrospective study of nine patients diagnosed with brainstem dysgenesis monitored in an outpatients department.

RESULTS

The mean age of the patients was 5.5 years. Five presented alterations in the neuroimaging scan and, in the five with a neurophysiological study, the results showed it to be altered. Six presented muscular hypotonia, eight had amimia/hypomimia, six had central hypoacusis and five had gastrostomy. A third of them presented an episode of cardiorespiratory arrest. Delayed psychomotor skills were detected in all cases. Currently five of them are capable of walking autonomously indoors and four of them outdoors. A high percentage of them (77.7%) understand simple orders and are capable of communicating (66.6%).

CONCLUSIONS

Alterations affecting the cranial nerves and muscle tone together with dysphagia are the most common manifestations in our population. The risk of bronchial aspiration and cardiorespiratory arrest is a threat to the lives of these patients. All the children present psychomotor retardation and half of them manage to accomplish autonomous walking. Given the diversity of the disability displayed by these patients, we believe a personalised, integral rehabilitative treatment is needed to obtain an optimal level of functioning. Further studies with wider samples are required to be able to obtain homogeneous groups and to establish the functional prognosis and needs in terms of rehabilitative treatment.

Radiological features of horizontal gaze palsy with progressive scoliosis. An 'Aunt Minnie' diagnosis?

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare autosomal recessive disorder characterized by congenital absence of normal horizontal eye movements and progressive scoliosis through childhood and adolescence. The characteristic radiological features in HGPPS are butterfly configuration of the medulla, split pons sign, selective volume loss of dorsomedial brainstem, relatively spared cerebellum, relatively prominent inferior olivary nucleus and absent posterior prominence of the facial colliculi and gracilis and cuneate nuclei. These radiological features are reflective of ROBO3 gene mutation required for hindbrain axon midline crossing. Awareness of this diagnosis is important as the radiological features are characteristic enough to be considered as a rare 'Aunt Minnie' and a radiologist may be the first one to raise the possibility of this diagnosis as in this case.

Severe second-trimester obstructive ventriculomegaly related to disorders of diencephalic, mesencephalic and rhombencephalic differentiation

By review of a series of cases, we set out to identify sonographic features suggestive of an obstructive mechanism in second-trimester fetuses with ventriculomegaly and describe developmental disorders related to pathological differentiation of the diencephalon, mesencephalon and rhombencephalon that lead to obstruction of cerebrospinal fluid flow. We studied retrospectively 11 fetuses referred for severe second-trimester ventriculomegaly of undetermined origin. Neurosonography was performed with detailed analysis of the third ventricle, thalami, cerebral aqueduct and cerebellum. The cerebral imaging data were compared with neuropathological data in eight patients, with a focus on the level and etiology of the obstruction. Parenchymal thinning and reduction of the pericerebral spaces were highly suggestive of ventriculomegaly due to an obstructive mechanism. The ventriculomegaly was related to diencephalosynapsis (thalamic fusion and third ventricle atresia) in five cases and partial/complete aqueduct stenosis in six; it was associated with cerebellar hypoplasia in six cases, including rhombencephalosynapsis in two cases. In nine patients, disorders of the diencephalon, mesencephalon and rhombencephalon were present. In cases of severe isolated ventriculomegaly in which sonographic features are suggestive of an obstructive mechanism, close examination of the third ventricle, thalami, aqueduct of Sylvius and cerebellum may reveal pathological differentiation of the diencephalon, mesencephalon or rhombencephalon, often in combination.

Neonatal Food Restriction Induces Hypoplasia in Developing Facial Motor Neurons of Rats

The effects of neonatal food restriction upon the dendritic development of facial nucleus (FN) motor neurons of Wistar rats were analyzed. Rats neonatally underfed by daily (12 h) mother-litter separation in an incubator from 5-30 days after birth exhibited, in brain stem Golgi-Cox sections, significant reductions in the number and extension of stellate, triangular and bipolar FN neuronal dendritic prolongations with negligible effects upon perikarya measurements. Data suggest that in the underfed newborn, the ability of FN neurons to establish synaptic contacts with afferent fibers is reduced, which then interferes with their capacities for the integration and triggering of nerve impulses to modulate facial motor expression in response to sensory cues.

Cavernous malformations and hemorrhage risk

Widespread availability of magnetic resonance imaging has helped our understanding of the natural history of cavernous malformations (CMs) of the brain. CMs present with diverse clinical manifestations. Supratentorial CMs are often identified incidentally. The clinical presentation corresponds with lesion location. Symptomatic, hemorrhagic CMs of the brainstem pose a challenging clinical problem as they are often associated with high surgical morbidity. In order to study the natural history of CM, we performed a prospective analysis on a series of patients who were sent to us for management. During the mean prospective follow-up interval of 34 months, 9 hemorrhages occurred. History of prior hemorrhage was the most important risk factor for subsequent hemorrhage. The annual hemorrhage was 0.6% in patients who never had a symptomatic hemorrhage. Patients who had prior hemorrhage have a higher (4.5%) annual hemorrhage rate.

Radiosurgery for brainstem arteriovenous malformation

The authors outlined the treatment result of arteriovenous malformations (AVMs) inside the brainstem by reviewing the 4 existing studies in detail. The majority of patients with brainstem AVMs had a history of hemorrhage, leading to neurological deficits at the time of treatment in 72-73% of patients. The most frequent location was the midbrain or the pons depending on studies, while the medulla oblongata was the least common location throughout the series. The obliteration rate after radiosurgery was 44-73%, which was generally lower than in other locations, while the complication rate was 5-14%, which was expectedly higher than in other locations. No objective evidence for size is known, and therefore, patient selection and treatment planning should be carefully performed after judicious assessment of treatment risks and benefits among limited treatment options.

[Ocular coloboma and results of brain MRI: preliminary results]

INTRODUCTION

Congenital ocular colobomas are the result of a failure in closure of the embryonal fissure. We present a prospective study (2007-2011) in which we report brain MRI findings in children with ocular coloboma.

PATIENTS AND METHODS

Thirty-five children (54 eyes) were included; 15 boys, 20 girls with a median age of 24.0 months (1.0-96.0) at first presentation. Within 2 to 3 months following complete ophthalmologic examination, brain MRI was performed.

RESULTS

Colobomas were bilateral in 19 cases and unilateral in 16 cases. Eleven different types of coloboma were identified. Of 54 eyes, 74% demonstrated optic nerve coloboma, of which 28 were severe. Of 35 MRI's performed, abnormalities were present in 86%: gyration abnormalities (n=21), lateral ventricular dilatation (n=17), dilatation of the Virchow-Robin and subarachnoid spaces (n=14), signal abnormalities and brain stem malformations (n=14), white matter signal abnormalities (n=11), corpus callosum abnormalities (n=10). Most of these abnormalities were related. Gyration abnormalities were the most frequent. There was no significant association between the severity of the coloboma and the abnormalities found (P=1.0). Likewise, there was no significant association of gyration abnormalities with the severity of coloboma in children (P=1.0).

DISCUSSION AND CONCLUSION

This study shows, for the first time, the existence of frequent cerebral abnormalities on MRI in children with ocular coloboma. The most common abnormality being gyration abnormalities, in 60% of cases.

Brainstem-vermis and brainstem-tentorium angles allow accurate categorization of fetal upward rotation of cerebellar vermis

OBJECTIVE

To evaluate the role of the brainstem-vermis (BV) and brainstem-tentorium (BT) angles in the differential diagnosis of upward rotation of the fetal cerebellar vermis.

METHODS

The BV and BT angles were measured retrospectively on median sonographic views of the brain in 31 fetuses at 19-28 weeks' gestation with upward rotation of the cerebellar vermis due to Blake's pouch cyst (n = 12), Dandy-Walker malformation (n = 12) and cerebellar vermian hypoplasia (n = 7). Eighty normal fetuses at 20-24 weeks were included as controls.

RESULTS

In the control group, BV and BT angles were 9.1 ± 3.5° (range, 4-17°) and 29.3 ± 5.8° (range, 21-44°), respectively. The BV angle was significantly increased in each of the three subgroups of anomalies: Blake's pouch cyst (23 ± 2.8°; range, 19-26°), vermian hypoplasia (34.9 ± 5.4°; range, 24-40°) and Dandy-Walker malformation (63.5 ± 17.6°; range, 45-112°), the angle increasing with increasing severity of the condition. The BT angle had a similar pattern but there was overlap among the different groups.

CONCLUSION

The BV angle and, to a lesser degree, the BT angle are simple and reproducible measurements that provide valuable additional information for the categorization of upward rotation of the fetal cerebellar vermis. From mid gestation, a BV angle > 45° is strongly suggestive of a Dandy-Walker malformation, while a measurement < 30° favors the diagnosis of a Blake's pouch cyst.

Cerebellar hypoplasia and brainstem thinning associated with severe white matter and basal ganglia abnormalities in a child with an mtDNA deletion

Cerebellar and brainstem hypoplasia may occur in different conditions, including those disorders designated as pontocerebellar hypoplasia (PCH). In particular, when PCH is combined with severe supratentorial white matter involvement and cerebral atrophy, mutations in the mitochondrial arginyl-tRNA synthethase (RARS2) gene causing PCH6 are possible. We describe a patient with a lethal mitochondrial encephalomyopathy due to a mtDNA deletion and no alterations in RARS2, whose magnetic resonance (MR) findings mimicked PCH6. A thorough diagnostic work-up for mitochondrial disorders should be carried out when facing with a PCH-like and severe white matter and basal ganglia involvement on brain MR imaging in children, even if clinical and laboratory mitochondrial "stigmata" are scant or nonspecific.

Bilateral complete labyrinthine aplasia with bilateral internal carotid artery aplasia, developmental delay, and gaze abnormalities: a presumptive case of a rare HOXA1 mutation syndrome

The human HOXA1 mutation syndromes commonly present with abnormalities of the inner ear and ICAs. Previous cases describe varying degrees of hypoplasia or aplasia of the affected structures, often with asymmetric involvement. We present imaging findings documenting complete absence of the ICAs bilaterally with bilateral CLA, which, to our knowledge, has not been previously reported.

Neuronopathic Gaucher disease: demographic and clinical features of 131 patients enrolled in the International Collaborative Gaucher Group Neurological Outcomes Subregistry

OBJECTIVE

To describe demographic, genetic, and clinical characteristics of patients with neuronopathic Gaucher disease (NGD).

METHODS

All patients enrolled in the Neurological Outcomes Subregistry of the International Collaborative Gaucher Group (ICGG) Gaucher Registry as of June 2007 were identified.

RESULTS

The study cohort comprised 131 patients from 17 countries who were enrolled in the Neurological Outcomes Subregistry. The onset of neurological manifestations had occurred before 2 years of age in 47% (61 out of 131 patients), 2 years of age or older in 41% (54 out of 131), and could not be ascertained in the remaining 12% (16 out of 131). The most common manifestations were inability to look to the extreme up or down (45%, 55 out of 123), abnormally slow object tracking (43%, 53 out of 123), convergent squint (36%, 44 out of 121), and ataxia (15 to 20%, 18-27 out of 117). Seizures were reported in 19 out of 122 patients (16%), and myoclonic seizures were reported in 3 out of 121 patients (2%). The most common genotypes were L444P/L444P (76 out of 108, 70%), L444P/D409H (9 out of 108, 8%), D409H/D409H (8 out of 108, 7%), and L444P/rare allele (6 out of 108, 6%); full sequencing was not performed in all patients.

CONCLUSIONS

Neurological manifestations of GD often begin to appear before the age of 2 years. The most common neurological signs and manifestations are brainstem abnormalities and fine motor dysfunction. The most common genotype is L444P/L444P.

Repair of Chiari III malformation using cranioplasty and an occipital rotation flap: technical note and review of literature

BACKGROUND

Chiari III malformation (CM3) is rare among Chiari malformations (I-IV). Its definition has been expanded to include caudal medullary displacement and hindbrain herniation into encephaloceles in lower occipital and high cervical regions. Prognosis is recorded as dismal, with respect to survival and functional outcome.

METHODS

We describe the presentation, radiologic evaluation, and repair of this malformation using methyl-methacrylate cranioplasty and an occipital scalp rotation flap for closure. Outcome after surgery is addressed.

RESULTS

Adequate closure of the defect and protection of underlying structures was achieved without undue stress at incision site.

CONCLUSIONS

This method of closure can be considered in cases of large occipital and cervical encephaloceles with poor skin cover and added osseous anomalies around the foramen magnum.

Diffusion tensor imaging demonstrates brainstem and cerebellar abnormalities in congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome (CCHS) patients show reduced breathing drive during sleep, decreased hypoxic and hypercapnic ventilatory responses, and autonomic and affective deficits, suggesting both brainstem and forebrain injuries. Forebrain damage was previously described in CCHS, but methodological limitations precluded detection of brainstem injury, a concern because genetic mutations in CCHS target brainstem autonomic nuclei. To assess brainstem and cerebellar areas, we used diffusion tensor imaging-based measures, namely axial diffusivity, reflecting water diffusion parallel to fibers, and sensitive to axonal injury, and radial diffusivity, measuring diffusion perpendicular to fibers, and indicative of myelin injury. Diffusion tensor imaging was performed in 12 CCHS and 26 controls, and axial and radial diffusivity maps were compared between groups using analysis of covariance (covariates; age and gender). Increased axial diffusivity in CCHS appeared within the lateral medulla and clusters with injury extended from the dorsal midbrain through the periaqueductal gray, raphé, and superior cerebellar decussation, ventrally to the basal-pons. Cerebellar cortex and deep nuclei, and the superior and inferior cerebellar peduncles showed increased radial diffusivity. Midbrain, pontine, and lateral medullary structures, and the cerebellum and its fiber systems are injured in CCHS, likely contributing to the characteristics found in the syndrome.

Massive diminution of the cervical spine: one case report

The authors report a 13-year-old female with shunted hydrocephalus who when evaluated for neck pain, was found to have not only fusion of cervical vertebrae but significant diminution of the cervical spine. Following our review of the classification of KFA and our case report, the current interpretation of Klippel and Feil's original description of KFA should be re-evaluated, and/or a new class of KFA used, that of complete or partial cervical vertebrae agenesis and associated abnormalities, should be considered in the classification of this anomaly.

Fourth ventriculoceles with extracranial extension: one case report

Encephaloceles involving only the herniated fourth ventricle are exceedingly rare. We report a case of such a cranial malformation and review the literature regarding these malformations and their potential embryological derailment.

Sudden death due to central alveolar hypoventilation syndrome (Ondine's curse) in a 39-year-old woman with heterotopia of the inferior olive

Failure of automatic involuntary respiration with preservation of voluntary respiratory drive (Ondine's curse) is a rare occurrence which has been reported following a variety of morphologic lesions near respiratory centers in the lower brainstem. We report the case of a 39-year-old woman with a syndrome of fulminant respiratory failure with features of Ondine's curse in whom neuropathologic examination disclosed a preexisting malformation of the lower brainstem, as well as acute local subarachnoid bleeding. Mechanisms in the present case are discussed and a review of similar cases published so far is given. The necessity of sound investigation, including neuropathologic studies in cases of sudden unexplained death, is underlined.

[Chronic facial pain due to a brainstem cavernoma]

Idiopathic trigeminal neuralgia is almost always associated with pathological nerve/vessel contact. Symptomatic forms of trigeminal neuralgia include cases of multiple sclerosis, infratentorial tumours and postherpetic neuralgia. Vascular malformations causing neuralgia have rarely been reported. We present the case of a 55-year old woman, who suffered from facial pain and ptosis on her left side. Repeated neurological examinations as well as repeated magnetic resonance imaging did not lead to a definite diagnosis or therapy. The pain suddenly stopped three weeks before admission and only a slight left sided facial hypaesthesia persisted. Reevaluating the older MRI we found a small signal alteration of 2 mm in the caudal part of the left trigeminal nucleus. A new MRI showed a subacute haemorrhage into a small brainstem cavernoma, which must have caused the pain and later on the hypaesthesia. Small vascular malformations are a rare cause of neuropathic facial pain.

A new locus for autosomal recessive spastic paraplegia (SPG32) on chromosome 14q12-q21

Hereditary spastic paraplegias (HSPs) are a group of neurodegenerative disorders characterized by progressive spasticity of the lower limbs. Here, we performed a genome-wide linkage analysis on a consanguineous family presenting an autosomal recessive form of HSP associated with mild mental retardation, brainstem dysraphia, and clinically asymptomatic cerebellar atrophy. We have mapped the disease locus SPG32 to chromosome 14q12-q21 within a 30-cM interval, which excludes the atlastin gene.

Smooth ocular pursuit in Chiari type II malformation

Chiari type II malformation (CII) is a congenital anomaly of the cerebellum and brainstem, both important structures for processing smooth ocular pursuit. CII is associated with myelomeningocele and hydrocephalus. We investigated the effects of CII on smooth pursuit (SP) eye movements, and determined the effects of spinal lesion level, number of shunt revisions, nystagmus, and brain dysmorphology on SP. SP was recorded using an infrared eye tracker in 21 participants with CII (11 males, 10 females; age range 8-19y, mean 14y 3mo [SD 3y 2mo]). Thirty-eight healthy children (21 males, 17 females) constituted the comparison group. Participants followed a visual target moving sinusoidally at +/- 10 degrees amplitude, horizontally and vertically at 0.25 or 0.5Hz. SP gains, the ratio of eye to target velocities, were abnormal in the CII group with nystagmus (n= 8). The number of shunt revisions (range 0-10), brain dysmorphology, or spinal lesion level (n= 15 for lower and n= 6 for upper spinal lesion level) did not correlate with SP gains. SP is impaired in children with CII and nystagmus. Abnormal pursuit might be related to the CII dysgenesis or to effects of hydrocephalus. The lack of effect of shunt revisions and abnormal tracking in participants with nystagmus provide evidence that it is related primarily to the cerebellar and brainstem malformation.

Disorders of cerebellar growth and development

PURPOSE OF REVIEW

This review summarizes for the pediatrician the current understanding of normal cerebellar and brainstem development, and then discusses selected malformations to highlight advances in the area. The impact of prematurity on cerebellar growth and development is then examined. The important insights provided by recent neuroimaging and genetic advances are reviewed.

RECENT FINDINGS

Previous areas of dispute are being addressed by advances in two major areas. Advanced neuroimaging studies during fetal and postnatal life are now providing important insights into the nature of normal and abnormal development of the brainstem and cerebellum. These powerful new techniques for defining morphology in vivo, together with major advances in genetics, are accelerating our understanding of genotype-phenotype relationships. Conversely, the ability to link early brain injury to subsequent cerebellar development has challenged previous understanding of the distinction between acquired and primary dysgenesis, presumed to be genetic in origin.

SUMMARY

The synthesis of a rational and clinically useful classification of posterior fossa malformations has been elusive. Recent developments promise to resolve ongoing disputes that have delayed progress. However, these insights into disturbed structural development demand rigorous examination of their long-term functional significance and caution before their prognostic significance is applied clinically.

Brainstem Anomalies in Two Patients Affected by Congenital Central Hypoventilation Syndrome

Congenital central hypoventilation syndrome (CCHS) is a rare neurocristopathy characterized by absence of automatic control of respiration; decreased sensibility to hypoxia and hypercapnia, mainly during sleep; and autosomal dominant inheritance due to heterozygous polyalanine expansions and frameshift mutations in the PHOX2B gene. Because the CCHS phenotype could hide other neurologic diseases, the American Thoracic Society established that the initial evaluation of suspected CCHS should exclude neuroanatomic impairments as the structural basis of the reduced autonomic system function. In this work, we describe the clinical history of two unrelated patients with hypoventilation during sleep and harboring hypoplasia of the pons and a Chiari I malformation, respectively. In both patients, CCHS was diagnosed by detection of PHOX2B polyalanine expansion, suggesting that the American Thoracic Society diagnostic criteria may be too restrictive. Moreover, to exclude a putative role of PHOX2B in non-CCHS neurologic diseases, we have performed PHOX2B mutation screening in a group of individuals with Chiari I malformation, confirming the exclusive role of PHOX2B in the pathogenesis of CCHS.

Isolated Dandy-Walker malformation associated with brain stem dysgenesis in male sibs

We describe two brothers with isolated Dandy-Walker malformation (DWM). Interestingly, brain stem dysgenesis and abnormal gyral pattern were also observed in the sibs. They presented with psychomotor retardation and macrocrania. Both suffered from hypotonia with brisk deep tendon reflexes and ataxic gait. They had bilateral optic atrophy and the visual evoked potentials documented prolonged latencies. Further, motor and sensory conduction velocities were normal. Chromosomal examinations for the sibs and their parents showed normal results. The majority of cases are sporadic but rare reports of recurrence in siblings exist. The parents' consanguinity and the recurrence in a subsequent pregnancy suggest an autosomal recessive inheritance pattern. Our report adds more weight that brain stem dysgenesis could be associated with DWM, increasing the spectrum of heterogeneity of this malformation.

Basicranial diplomyelia: an extension of the split cord malformation theory. Case report

Basicranial diastematomyelia is an extremely rare congenital disorder. A review of the literature indicates only one reported case of basicranial diastematomyelia in which an osseous peg divided the brainstem in two. The authors present the first reported case of basicranial diplomyelia split by a fibrous band and correlate its pathogenesis with that of split cord malformation (SCM). The patient described in the present report had a fibrous stalk dividing the brainstem, and therefore the condition was categorized as a diplomyelia, or SCM Type II. Because the occipital dermatomes behave similarly to the spinal dermatomes early in development, they may be subject to the same embryonic error that results in SCM. The authors propose that the mechanism leading to SCM is the same as that found in basicranial split malformations and that the theory explaining it be modified to include the posterior fossa.

Cavernous malformations of the brainstem in infants. Report of two cases and review of the literature

Cavernous malformations of the brainstem (CMB) occur less commonly in children than in adults. Their appearance is even rarer in infants, with only five cases reported in the literature. The authors report two additional cases in which giant CMBs were diagnosed in two infants, one when the patient was 1 month old and the other when the patient was 15 months old. A median suboccipital approach in one patient and a pterional-orbitozygomatic approach in the other were used to obtain complete resection of the malformations. Excellent outcomes were achieved in both children. A review of the literature is also presented. It seems that CMBs in infants usually follow a progressive course of growth and associated neurological deterioration. Patients with symptomatic lesions abutting the pial surface should undergo surgical treatment with the goal of cure. An increase may be expected in the number of CMBs diagnosed in children as a result of regular screening of relatives with the familial form of the disease. Nevertheless, due to the small confines of the brainstem, incidental or asymptomatic CMB should still be extraordinary. In the case of such a rare occurrence, conservative treatment should be advocated.

Tethered brainstem repair and near-fatal ventriculoperitoneal shunt insertion. Case report

The authors report a case of primary brainstem tethering, a component of a spinal dysraphic state, occurring in a 13-year-old girl. This patient also had associated hydrocephalus, a low-lying tethered cord, and a syrinx in her conus medullaris. The significance of imaging surveys of the craniospinal region and head in a case involving a low-lying tethered cord is highlighted. The insertion of a ventriculoperitoneal shunt, leading to traction on the tethered brainstem, proved nearly fatal for this patient. In cases involving a multiple-level tethered cord, the sequence of detethering should be decided on with caution. It seems prudent to detether the vital neural structure first, so as to minimize the traction force on that structure. All four previously reported cases of secondary tethered brainstem and cerebellar vermis in the literature are reviewed and compared with the present case of primary brainstem tethering. The literature describing brainstem dysfunction caused by ventricular drainage is also reviewed.

MR imaging features of brain stem hypoplasia in familial horizontal gaze palsy and scoliosis

We report the case of a child with horizontal gaze palsy, pendular nystagmus, and discrete thoracolumbar scoliosis. MR imaging of the brain depicted pons hypoplasia with an absence of the facial colliculi, hypoplasia, butterfly configuration of the medulla, and the presence of a deep midline pontine cleft (split pons sign). These MR imaging findings suggest familial horizontal gaze palsy with progressive kyphoscoliosis, a rare congenital disorder. To the best of our knowledge, MR imaging findings of only 4 similar cases, with or without progressive idiopathic scoliosis, have been reported. We discuss the pathogenesis substratum of this entity. Early recognition of this rare entity is important if supportive therapeutic measures in progressive scoliosis are to be applied.

6q Terminal Deletion Syndrome Associated with a Distinctive EEG and Clinical Pattern: A Report of Five Cases

PURPOSE

Mental retardation, facial dysmorphisms, and neurologic and brain abnormalities are features of 6q terminal deletions. Epilepsy is frequently associated with this chromosome abnormality, but electroclinical findings are not well delineated. We report five unrelated patients with 6q terminal deletions and a peculiar clinical, EEG, and neuroradiologic picture of epilepsy, mental retardation, and colpocephaly.

METHODS

These three male and two female patients underwent general and neurologic examinations, repeated awake and sleep EEGs, and brain magnetic resonance imaging (MRI). A cytogenetic study and fluorescent in situ hybridization (FISH) with chromosome-specific subtelomeric probes were carried out in all cases.

RESULTS

All subjects had seizures characterized by vomiting, cyanosis, and head and eye version, with and without loss of consciousness. In four cases, EEGs showed posterior spike-and-wave complexes, which were activated by sleep. No patient had status epilepticus or prolonged seizures. Brain MRI revealed colpocephaly and dysgenesis of the corpus callosum and brainstem in four patients; three of them also had hypertrophic massa intermedia. FISH analysis revealed a 6q terminal deletion in all patients, which ranged between 9 Mb (cases 2 and 3) and 16 Mb (case 4).

CONCLUSIONS

We suggest that epilepsy associated with 6q terminal deletions is a new entity. Patients with dysmorphic features associated with focal occipital epilepsy, colpocephaly, and dysgenesis of the corpus callosum, thalami, and brainstem should be considered candidates for testing for 6q subtelomere deletions.

Congenital unilateral multiple cranial neuropathy: an etiology shared with Mobius syndrome?

Mobius syndrome was originally described as bilateral 6th and 7th cranial nerve palsy and has since been expanded to include involvement of nearly all cranial nerves, limb deformities, orofacial anomalies and deficits in intellectual function. The etiology of Mobius syndrome remains elusive. Here we present a case with unilateral 5th, 7th, 9th, 10th and 12th cranial nerve palsy along with MRI evidence of ipsilateral brainstem hypoplasia. We propose the unilateral pathology supports the theory that vascular malformation in utero, which can be due to various etiologies, leads to brainstem ischemia and is the key factor in development of Mobius syndrome.

Brain stem and cerebellar findings in Joubert syndrome

Joubert syndrome is often missed clinically and radiologically if not enough attention is paid to its subtle and variable clinical presentation and the imaging findings in the posterior fossa. The purpose of this paper is to illustrate the brain stem and cerebellar imaging findings in Joubert syndrome. Awareness of the clinical and neuroimaging findings in Joubert syndrome and maintenance of a high index of suspicion are essential to correctly diagnose this rare congenital malformation.